please help large count of error i don't know why

[Altera_Forum]

this is my code i write it step by step but alarge amount of error appear i can't fix it can u help  

-----------------------------------------  library ieee; use ieee.std_logic_1164.all; ------------------------------------------------------------------ entity heat_sys is port (manual_sig ,outside_sig ,room_sig:in std_logic; specific_time_hours,timer_hours:integer range 0 to 24; timer_miniut,specific_time_miniut:integer range 0 to 60; keybad_inp:std_logic_vector (3 downto 0); heat_value:integer range 0 to 38; heat_on_off : buffer std_logic); end entity; ------------------------------------------------------------------ architecture heat_sys_beh of heat_sys is begin process (manual_sig,outside_sig,room_sig,heat_value,keybad_inp,specific_time_hours,timer_hours,timer_miniut,specific_time_miniut) begin if outside_sig ='1' then if ((timer_hours= specific_time_hours) and (timer_miniut=specific_time_miniut)) then ---------------------------------------------------------------------- if keybad_inp(0)='1' then if heat_value >=38 then heat_on_off='0'; else heat_on_off='1'; end if; elsif keybad_inp(1)='1' then if heat_value >=30 then heat_on_off='0'; else heat_on_off='1'; end if; elsif keybad_inp(2)='1' then if heat_value >=36 then heat_on_off='0'; else heat_on_off='1'; end if; else if heat_value >=18 then heat_on_off='0'; else heat_on_off='1'; end if; end if; ------------------------------------------------------------------------- else heat_on_off <='0'; end if; ------------------------------------------------------------------------- elsif room_sig ='1' then if keybad_inp(0)='1' then if heat_value >=38 then heat_on_off='0'; else heat_on_off='1'; end if; elsif keybad_inp(1)='1' then if heat_value >=30 then heat_on_off='0'; else heat_on_off='1'; end if; elsif keybad_inp(2)='1' then if heat_value >=36 then heat_on_off='0'; else heat_on_off='1'; end if; else if heat_value >=18 then heat_on_off='0'; else heat_on_off='1'; end if; end if; ------------------------------------------------------------------------------- elsif manual_sig ='1' then if keybad_inp(0)='1' then if heat_value >=38 then heat_on_off='0'; else heat_on_off='1'; end if; elsif keybad_inp(1)='1' then if heat_value >=30 then heat_on_off='0'; else heat_on_off='1'; end if; elsif keybad_inp(2)='1' then if heat_value >=36 then heat_on_off='0'; else heat_on_off='1'; end if; else if heat_value >=18 then heat_on_off='0'; else heat_on_off='1'; end if; end if; --------------------------------------------------------------------------- else heat_on_off <='0'; end if ; end process; end architecture ;

[Altera_Forum]

To begin with you should define all entity signals as either inputs or outputs. You have missed some. 

 What does the error say

[Altera_Forum]

thanks for ur help but i know my error lately may cause of the large of the program  

error was signals inputs or outputs as u say and i do = instead of <= in heat_on_off signal  soooo thanks for ur help  the program know work in the write way ^_^